A potential DNA protector, enzyme inhibitor and<i> in</i><i> silico</i> studies of daucosterol isolated from six<i> Nepeta</i> species

Daucosterol (DAU) was isolated from the methanol-chloroform crude extract of six Nepeta species (N. N. aristata, , N. baytopii, N. italica, N. nuda albiflora, N. stenantha and N. trachonitica) ) using sephadex and silica-gel columns via bioactivity-guided isolation. Spectroscopic methods and comparisons with similar data in the literature determined its structure. DAU was evaluated for enzyme inhibitions, kinetics, DNA protection, and molecular interactions. The inhibition activities of AChE, tyrosinase, BChE, and urease were found to be 21.32+1.24, 3.17 +0.45, 16.73+0.10 and 12.95+0.21 mu M, respectively. The Ki i values of the inhibition kinetics of the same enzymes were observed as 0.11, 0.05, 0.12, and 0.12 mM, respectively. DAU exhibited effective protection activity against DNA damage induced by H2O2 and ultraviolet radiation in DNA protection tests. DFT analysis showed low hardness and high softness values. The best binding affinity of DAU was achieved by the enzymes AChE and BChE (for both:-9.90 kcal/mol). As a result of the interaction of standards and DAU with enzymes, it was observed that DAU bound with a higher potential than the standards. Molecular dynamics simulations of these enzymes were examined for 100 ns, and the energy results of the simulation were determined by MM/PBSA calculation in the last 10 ns. Additionally, its pharmacokinetic properties were investigated with SwissADMET, and it was noted that it had low toxic effects and gastrointestinal absorption. Thus, in vitro and in silico analysis determined that the DAU molecule could protect against DNA oxidative damage and an active metabolic enzyme inhibitor.